Derek Cohen made mention of using a sumitsubo and a centerline in marking out in another thread. I have an interest in centerline marking also. Not so much in the use of a sumitsubo but using a centerline. This is how I approach it. I only use it for shorter things like mortises. I use a 6” rule. I mark a center on the work with a .5 pencil. I then center my measurement on the line using the 1/32 scale. I then mark off the end of the scale with .5 pencil only allowing the lead to touch the scale not the lead holder. I then mark the opposing side in the same fashion. Mark another center and edges further along the work. Mark the edge lines using the scale. Your cut line will be on the inside edge of the pencil line. In my experience it is very accurate. Within 1/128” or closer. How do you approach using centerlines?